Abstract

As part of the ‘National Hydrographic and Oceanographic Research Plan for the Spanish Exclusive EconomicZone’, multibeam bathymetry and seismic reflection profiles were obtained in the Canary Islands aboard the R/VHespérides. The submarine flanks of the Anaga offshore extension of Tenerife Island are here studied to analyze itsgeomorphology. In the north sector of the Anaga submarine massif, the extension of the Anaga Debris Avalanchehas been mapped for the first time, and a volume of 36 km3 was calculated. The relationship between the Anagaand Orotava Debris Avalanches is also described. Faulting has been recognized as a key process for the occurrenceof debris avalanches and the growth of volcanic lineaments. Moreover, faulting affects previous structures and thechannelling of debris flows. Structural analysis shows the typical radial pattern of an oceanic island. In addition, aNE-SW dominant direction of faulting was obtained, consistent with the Tenerife Island structural trend seen in theAnaga Massif and Cordillera Dorsal. NW-SE and E-W are two other main trends seen in the area. Special interestis manifest in two long faults: ‘Santa Cruz Fault’ bounds the southern edge of Anaga offshore Massif with a lengthof 50 km and a direction that changes from NE-SW to almost E-W. The Güimar Debris Avalanche was probablychanneled by this fault. The ‘Guayotá Fault’ was recognized in several seismic profiles with a N-S direction thatchanges towards NW-SE at its southern end. This fault affects the more recent sediments with a vertical offset of25–30 m, along 60 km. It has been interpreted as a transpressive strike-slip fault.